Device for joining strips of a flexible material

Abstract

A device is provided to join the lower end of a strip of paper coming from a nearly-empty reel to the upper end of another strip of paper coming from a full reel. The joining device comprises a rotating striking arm equipped with a hammer on one of its ends and with a cam on the other end. When the join between two strips is to be made, a jack actuates a castor which butts against the cam, thus bringing a striking surface of the hammer closer to the strips to compress and join the strips. The device further comprises a front and a rear cutting fixture permitting the remaining ends of the strips of paper to be cut on either side of the join. Air bearings are provided to guide one or both strips.

We claim: 
     
       1. An apparatus for joining a portion of length of a first strip of a flexible material to a portion of length of a second strip of flexible material, the two strips traveling at an equivalent velocity in the same direction along approximately parallel paths and being in contact one on the other while on a peripheral surface sector of a join roller, the device comprising: a rotatable striking arm rotating in a circular path having a direction of rotation and positioned such that the velocity of the first and second strips is tangential to the circular path in the direction of the circular path, said striking arm having a rotary support, a hollow rotation shaft, and at least one rod adapted to slide radially within the hollow of said rotary support,   a radially extensible hammer fixed to one end of the rod and including a striking surface, said hammer, over a portion of the circular path of rotation of said striking arm, presenting said striking surface in immediate contacting proximity to the two strips on the join roller travelling at the same tangential speed as the velocity of the first and second strips, and   a radial displacement means for selectively maintaining the location of the hammer and for extending the hammer, said radial displacement means comprising a spring for normally biasing the hammer in a retracted position, and a cam fixed to a second end of the rod opposite the first end, said cam being connected to a jack,   whereby the jack displaces the rod and hammer to move the hammer to a radially extended position and the two strips over their respective portions of length between said striking surface and the join roller are compressed with contacting force by radial extension of the hammer to form joined portions.   
     
     
       2. An apparatus according to claim 1, wherein said striking surface comprises at least two knurled portions separated by a groove, the groove arranged in the direction of velocity of the strips upon compression. 
     
     
       3. An apparatus according to claim 1, wherein said striking surface comprises at least two knurled portions separated by a groove, the groove arranged perpendicularly to the direction of velocity of the strips upon compression. 
     
     
       4. An apparatus according to claim 1, wherein, when said hammer is retracted, said striking arm accelerates in the circular path of rotation to the same tangential speed as the velocity of the first and second strips, and wherein said radially displacing means extends said hammer when said striking arm has the same tangential speed as the velocity of the first and second strips. 
     
     
       5. An apparatus according to claim 1, further comprising a motor, wherein said rotation shaft is connected to said motor, said motor being capable of holding said striking arm stopped at a given angular position and of causing said striking arm to pivot at a speed such that the tangential speed of said striking surface of said hammer is equal to the velocity of the strips. 
     
     
       6. An apparatus according to claim 1, further comprising control means for detecting that a supply of one of the strips of flexible material is below an established amount, for controlling the speed of rotation of said striking arm so that the tangential speed of said striking surface of said hammer is equal to velocity of the two strips, for actuating the jack when the angular position of the striking arm is in a first given position, for ceasing actuation of the jack when the strips have been joined, and for stopping the rotation of said striking arm at a second given angular position. 
     
     
       7. An apparatus according to claim 1, further comprising a front cutting fixture for cutting an end of the first strip of flexible material in front of the joined portions of the two strips and a rear cutting fixture for cutting the end of the second strip of flexible material behind the joined portions of the two strips. 
     
     
       8. An apparatus according to claim 7, wherein said hammer comprises a rod portion projecting from a side face of said hammer, and wherein said rear cutting fixture comprises a second cutting blade, a second retaining spring, and at least one second lever pivoting about an axis, one portion of said second lever supporting said second cutting blade, said second cutting blade having a length least equal to the width of the strips, said second retaining spring retaining said rear cutting fixture in a retained position, one end of said second lever being actuated by the rod portion projecting from the side face of said hammer for engaging said second cutting blade across the second strip of flexible material. 
     
     
       9. An apparatus according to claim 7, wherein said hammer comprises a rod portion projecting from a side face of said hammer, and wherein said rear cutting fixture comprises a cutting blade, a retaining spring, and at least one lever pivoting about an axis parallel to an axis of rotation of the join roller, one portion of said lever supporting said cutting blade, said cutting blade having a length least equal to the width of the strips, said retaining spring retaining said rear cutting fixture in a retained position, one end of said lever being actuated by the rod portion projecting from the side face of said hammer for engaging said cutting blade across the second strip of flexible material. 
     
     
       10. Joining device according to claim 7, wherein said hammer comprises a rod portion projecting from a side face of said hammer, and wherein said rear cutting fixture comprises a cutting blade, a retaining spring, and at least one lever pivoting about an axis parallel to an axis of rotation of the join roller, one portion of said lever supporting said cutting blade, said cutting blade having a length least equal to the width of the strips, said retaining spring retaining said rear cutting fixture in a retained position, one end of said lever being actuated by the rod portion projecting from the side face of said hammer for engaging said cutting blade across the second strip of flexible material. 
     
     
       11. An apparatus according to claim 7, wherein said hammer comprises two opposite side faces and a front face, and said front cutting fixture comprises a first cutting blade, first retention spring and two first levers pivotable about an axis and disposed on the two side faces of said hammer, said two first levers each comprising a front end extending beyond the front face of said hammer and supporting said first cutting blade, said first cutting blade having a length at least equal to a width of the strip, said first levers each further comprising a rearward end extending beyond said striking surface of said hammer, said first retention spring retaining said front cutting fixture in a retained position, said rearward ends of said first levers contacting a contact surface of the join roller to pivot said first cutting blade and engage said first cutting blade across the first strip of flexible material. 
     
     
       12. An apparatus according to claim 11, wherein said first cutting blade of the rear cutting fixture is engaged across the strips when said hammer is extended. 
     
     
       13. An apparatus according to claim 11, wherein said second cutting blade of the rear cutting fixture is engaged across the strips when said hammer is extended.